Strange things can happen when water turns to ice. In this case, there was a lot of rain, which filled the stair railing pipes with water, and then the temperature fell far below freezing. The water in the pipe froze on the outer edge first, so water inside was pushed out the hole, where it froze quickly as it emerged. When you see something like this, your first instinct is to take a picture. Then your second instinct is an urge to break it off, right?